An important consideration in the design of light fixtures is the selection of the light source. Fluorescent lamps have long been the light source of choice in many commercial applications, particularly for indoor office lighting. These fluorescent lamps provide high lumen output, which is a favorable quality when illuminating a space. Other light sources may include electrodeless high-intensity discharge (“HID”) lamps or incandescent light bulbs. Additionally, light-emitting diodes (“LED”) have grown in popularity as a light source due to their high lumen output and compact size.
But such light sources (particularly, fluorescent lamps and LEDs) may produce undesirable direct lighting. “Direct lighting” means that the light is only directed into the space immediately below the light fixture, which leaves other areas of the space dark. For example, if a light fixture having a fluorescent lamp is mounted to a ceiling of a room, then the floor immediately below the light fixture may be very bright, but the upper portions of walls in the room may be dark. The use of optics may reduce some direct lighting. Optics may include lenses, shields, or other covers with refractive surfaces that refract the light and make the light more uniform in the illuminated space. But even with optics, light fixtures cannot always distribute light throughout the entire space meant to be illuminated.
Additionally, such light fixtures are typically mounted on the wall or ceiling such that a user cannot change the direction of the emitted light. For example, a light fixture may have a rectangular housing that is mounted to the ceiling with bolts or screws. If the requirements of the space change—for example, if furniture is moved in the space—then such permanently mounted fixtures cannot adapt to meet the new lighting requirements.
Finally, light sources emit thermal energy and may become very hot, thus risking damage to the light fixture. For example, a HID lamp may reach temperatures of 800° C. If the light fixture has an optic, the optic may melt or burn. The light source may become damaged or the restrike time (the time it takes for a light source to turn on after it is turned off) may become unacceptably long. It thus becomes necessary to provide systems, such as heat sinks, to reduce the temperature of the light fixture. But introducing heat sinks also increases the number of parts in the light fixture, and accordingly, the weight, manufacturing costs, etc.
Thus, there exists a need for light fixtures that may distribute light into a particular desired location.
There exists a need for light fixtures that may adapt to changing conditions within an illuminated space.
There exists a need to remove heat from the light fixture.
There exists a need to reduce the number of parts in the light fixture.